From 7a2f516d9a7a62c15676ac450f7b4a58320481f4 Mon Sep 17 00:00:00 2001
From: Mike J Innes <mike.j.innes@gmail.com>
Date: Tue, 17 Mar 2020 13:49:28 +0000
Subject: [PATCH] Make Bernoulli produce Bools (#1079)

* Bernoulli returns bool
closes #1068

* fix bernoulli eltype

* fix cdf and ccdf
---
 Project.toml                         |  5 ++---
 src/univariate/discrete/bernoulli.jl | 10 ++++++----
 test/bernoulli.jl                    |  4 ++--
 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/Project.toml b/Project.toml
index a5a44c0e3c..1d6320773b 100644
--- a/Project.toml
+++ b/Project.toml
@@ -29,11 +29,10 @@ Calculus = "49dc2e85-a5d0-5ad3-a950-438e2897f1b9"
 Distributed = "8ba89e20-285c-5b6f-9357-94700520ee1b"
 FiniteDifferences = "26cc04aa-876d-5657-8c51-4c34ba976000"
 ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
+HypothesisTests = "09f84164-cd44-5f33-b23f-e6b0d136a0d5"
 JSON = "682c06a0-de6a-54ab-a142-c8b1cf79cde6"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
-HypothesisTests = "09f84164-cd44-5f33-b23f-e6b0d136a0d5"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
-test = ["Calculus", "Distributed", "FiniteDifferences", "ForwardDiff", "JSON",
-        "StaticArrays", "HypothesisTests", "Test"]
+test = ["Calculus", "Distributed", "FiniteDifferences", "ForwardDiff", "JSON", "StaticArrays", "HypothesisTests", "Test"]
diff --git a/src/univariate/discrete/bernoulli.jl b/src/univariate/discrete/bernoulli.jl
index 713b6cd7bc..f39232c911 100644
--- a/src/univariate/discrete/bernoulli.jl
+++ b/src/univariate/discrete/bernoulli.jl
@@ -38,7 +38,9 @@ end
 Bernoulli(p::Integer) = Bernoulli(float(p))
 Bernoulli() = Bernoulli(0.5, check_args=false)
 
-@distr_support Bernoulli 0 1
+@distr_support Bernoulli false true
+
+Base.eltype(::Type{<:Bernoulli}) = Bool
 
 #### Conversions
 convert(::Type{Bernoulli{T}}, p::Real) where {T<:Real} = Bernoulli(T(p))
@@ -83,11 +85,11 @@ pdf(d::Bernoulli, x::Bool) = x ? succprob(d) : failprob(d)
 pdf(d::Bernoulli, x::Int) = x == 0 ? failprob(d) :
                             x == 1 ? succprob(d) : zero(d.p)
 
-cdf(d::Bernoulli, x::Bool) = x ? failprob(d) : one(d.p)
+cdf(d::Bernoulli, x::Bool) = x ? one(d.p) : failprob(d)
 cdf(d::Bernoulli, x::Int) = x < 0 ? zero(d.p) :
                             x < 1 ? failprob(d) : one(d.p)
 
-ccdf(d::Bernoulli, x::Bool) = x ? succprob(d) : one(d.p)
+ccdf(d::Bernoulli, x::Bool) = x ? zero(d.p) : succprob(d)
 ccdf(d::Bernoulli, x::Int) = x < 0 ? one(d.p) :
                              x < 1 ? succprob(d) : zero(d.p)
 
@@ -104,7 +106,7 @@ cf(d::Bernoulli, t::Real) = failprob(d) + succprob(d) * cis(t)
 
 #### Sampling
 
-rand(rng::AbstractRNG, d::Bernoulli) = rand(rng) <= succprob(d) ? 1 : 0
+rand(rng::AbstractRNG, d::Bernoulli) = rand(rng) <= succprob(d)
 
 #### MLE fitting
 
diff --git a/test/bernoulli.jl b/test/bernoulli.jl
index 276a442ac2..e9961f8d39 100644
--- a/test/bernoulli.jl
+++ b/test/bernoulli.jl
@@ -1,5 +1,5 @@
 using Distributions
 using Test, Random
 
-@test typeof(rand(Bernoulli())) == Int
-@test typeof(rand(Bernoulli(), 10)) == Vector{Int}
+@test rand(Bernoulli()) isa Bool
+@test rand(Bernoulli(), 10) isa Vector{Bool}